diff --git a/src/main/java/org/olat/course/nodes/gta/ui/EditTaskController.java b/src/main/java/org/olat/course/nodes/gta/ui/EditTaskController.java
index 85c329ef4693bf505573bf079e59a97daa5764e0..ec6e83ac11d374b56e1766c592922fa8a3d03749 100644
--- a/src/main/java/org/olat/course/nodes/gta/ui/EditTaskController.java
+++ b/src/main/java/org/olat/course/nodes/gta/ui/EditTaskController.java
@@ -135,7 +135,7 @@ public class EditTaskController extends FormBasicController {
 		if(fileEl.getInitialFile() == null && fileEl.getUploadFile() == null) {
 			fileEl.setErrorKey("form.mandatory.hover", null);
 			allOk &= false;
-		} else if (!FileUtils.validateFilename(fileEl.getUploadFileName())) {
+		} else if (fileEl.getUploadFile() != null && !FileUtils.validateFilename(fileEl.getUploadFileName())) {
 			fileEl.setErrorKey("error.file.invalid", null);
 			allOk = false;
 		} else if(!replaceFile && fileEl.getUploadFile() != null) {